Gas-lift pumping apparatus



PI 28, 1931- M. T. ARCHER GAS LIFT IUMPING APPARATUS `Filed Jan. 9, 1928 3 Sheets-Sheet 2 April 28, 1931.

M. T. ARCHER GAS LIFT PUMPING APPARATUS Filed Jan.

9, 1928 5 seets-sheet 3 a 53 I 2T a 16a.

65a.` l l34u:

5s 55 f' 5s 16a E 1 @El 50a 56 I 34e 51a INVENTOR Ma/WML d thereto fluid tight in'any desired way as by `Patented Apr. 28, 1931 UNITED, STATES PATENT OFFICE .mmm-Tamar., or PITTSBURGH, PENNSYLVANIA, AssIGNoR To THE NATIONAL sUIfLrL'zSconrANY, O11` TOLEDO, OHIO, A CORPORATION or OHIO GAS-Lm TUMPING APPARATUS n --A'pplioation med January 9, 1928. Serial No. 245,475.

My invention relates toapparatuis for lifting liquid, such as oil, from wells by the use (11i a compressible fluid, such as gas, air or the 5 It is one object of this invention to effect and control the production of oil from wells by introducing or jetting into the oil a gaseous agent under pressure and controlling the same automatically by means of suitable valves operated or controlled by Bourdon tubes or equivalents, the said gaseous agent, in addition to its functioning in 'some cases as a gaseous piston, being injected or jetted into the oil to levitate the same and cause it to be lifted and discharged from the wells. Other objects will be understood better after the invention has been described in detail.

.This applica-tion is, as far as Figs. 1 and 2 are concerned, a continuation of my application Serial No. 198,448,1iled June 13, 1927, patent-,ed /Oea 9, 1928, No. 1,687,317, the specific invention shown by these figures being divided out of the said application.

Referring to the accompanying drawings,

F Fig. 1 shows partly in side elevation and partly in vertical section a well casing and tubing provided with one form of my invention and Fig. 2, a central vertical section on the line 2-2 on Fig. 1. Figs. 3, 4, 5 and 6 are views of like character with Fig. 1 but showing four additional forms of my invention. Fig. 7 is a central vertical section of a modified form of the lower portion of Fig. 6; and Fig. 8 is a section of Fig. 7 on the line 8 8.

Referring first to Figs. 1 and 2, 10 designates a well casing of any preferred construction and has within it the well tubing 11, which, like the casing 1Q, is supposed to extend up to the top of the well and to have attached to its lower end, as by the coupling 12, a valve unit, now to be described.

The valve unit has the special tubular fixed valve member or tubing length 13 having the annular series of ports 14. The lower end of the valve member 13 is screwed into the upper head 15 of a cylinder having the external wall or casing `16 screwed thereon flush with the periphery of the head 15. The lower end of the wall 16 has the lower head 17 fitted valve is open., Assuming the parts are as in lshizlilnking the wall thereon or by welding or The heads have vertical threaded lopenings v in which the ends of the pipe or tubing length 18 are screwed, the latter being in axial alinement with the member 13. The heads 15 and 17 and the concentric tubular members 16 and 18 form a fluid-tight annular chamber 19.

The sleeve valve member 20 is slidable on the member 13 between the coupling 12 and `the head 15 and has the ports 21 which reg- 1ster with the ports 14 when the member 20 is at its upper limit against the coupling 12, and which are below the ports 14 when the member 2O is at its lower limit, as shown.

The member 20 has connected thereto the upper end of rods 22 which extend down through the stuiiing boxes 23 in the head 15 and have their lower ends secured to the upper ring or collar 24 resting on the antifriction balls 25 on the upper face of the lower ring or collar 26. The hollow helical Bourdon spring 27, having its turns normally or naturally oval or flattened with their shortest axes parallel with the axis of the members 16 and 18, is seated between the collar 26 and the head 17. The upper end of the spring is tightly closed and soldered to the collar 26, while its lower end is left open and projects through the head .17 to which it is secured, as by soldering. The Bourdon spring is made preferably Afrom resilient material, such as tempered steel or hard drawn brass.

The head 1 5 is provided with a relief or check valve 32 which seats downwardly to prevent iuid from entering the chamber 19.

In order to make the valve member 20 quickly snap open and shut, I provide a number of springfpressed balls 29 adapted to be seated in the annular depression 30 in the 9U member 13 when thevalve member 20 is in its lower position and the valve is closed, and in the depression 31 inthe member 13 when the member 20 is in its upper position and the Fig. 1, any increasing pressure in the spring 27 will not immediately commence to open the valve, but upward pressure will be accumulated until it overcomes the resistance of. i

the ball 29 in thedepression 30, whereupomrloo the valve member 20 will be fquickly moved upwardly and cause the valve to be fully opened with a snap action. If the described snap action were absent, the spring would not have any accumulation of force, but would gradually lengthen and shorten, causing the valve to be gradually moved in closing and opening directions, and to be finally gradually closed and opened. Snap action prevents the possibility of the valve being held partly open, permitting the actuating gas to flow continuously and at the same time to set up a back pressure on the oil bearing and in the well.

In case the static head of oil in a wellis short, it ma be sucient to provide only one Y valve unit, ut in case the head of oil in the well is suiiiciently long, additional valve units may be connected in tandem to the valve unit .shown by means of the coupling 28 which but preferably like that already described.

The oil level being above the valve member 20, the static pressure of the annular column of oil extending from the surface thereof down to the bottom of the head 17 is transmitted to the interior of the spring 27 and tends to make the cross-section of its turns more nearly round, and consequently to make the spring longer, which tends to open the, valve. M

Before a string of tubing containing a series of the valves is lowered into a well, the valves are all in closed positions. After the string has been lowered into pumping position in a well, thestatic pressure in some ot the lower springs will cause their turns to become suciently rounded to cause the springs to lengthen enough to open the valves they control. Some of the valves near the top of the oil column will probably remain closed.

rEhe oil standing in the casing 10 above the uppermost valve unit and compressed gas being applied to the surface of this oil in the annulus between the casing 10 and the pump string, pressure is transmitted to the interior of the Bourdon spring 27, whereby the cross-section of the turns becomes more nearly round. When the pressure has increased to a certain degree the cross-section of the turns becomes sufliciently round to produce on the valve member 20 an upward force which overcomes the weight of the parts and the resistance of the balls 29, and the valve member 20 snaps upwardly to open position and is held therein by the balls seating in the depression 31. When the oil level reaches these open ports or if these ports are initially open, gas is jetted through them and into the ascending column of oil. The gas so jetted levitates the oil in the annular space above the ports and between the casing and the tubing and causes the levitated oil to rise to the surface of the well, where it is conducted to suitable receiving means. Thus the pressure transmitted from the column in the said anmost valve to such an extent that the spring' contracts, compelling the sleeve valve member 20 to drop and close the ports 14. After the valve closes the gas pressure forces Athe oil level in the annulus downwardly and the lower 'valves are operated in the same manner as already explained.

The antifriction device comprising the rings 24 and 26 and the balls' 25 allows thev ring 26 to rotate freely to relieve the torsional strains on the spring 27 as it lengthens and shortens.

The tension of the gas in the chamber 19 will'be such as to provide a suitable dierential ot pressure between the space in the chamber and in the interior of the spring associated therewith, to allow the turns to become sufficiently rounded for the purpose explained above.

1n .case the outer iuid under pressure in the annulus should leak through any of the several joints into the chamber 19 and create a pressure in the latter which interferes with the operation ot the spring in that chamber, the check valve 32 would be opened by the pressure in the chamber and the pressure therein-be reduced when pressure in the annulus lowers to a point below the internal pressure in space 19.

By the use of valves at different levels in a well the initial head against which the applied pressure operates is greatly reduced, the pressure required to lower the oil from the lirst to the second valve, and from the latter to the next, and so on is substantially the same as required to lower the oil to the first valve through the same distances as obtain between successive lower valves.

I have described the invention as operated bypressure applied to the annular iuid column within the casing 1, but the gas pressure may be applied on e oil column in the well tubing, the oil being discharged up through the casing 1.

1 have used the word gas generically, in-

tending that it shall cover any suitable {iuid 'of a gaseous nature, which includes air.

1anv

casings 33 and 34 are provided. The sealed rantifriction ring 24. The latter carries the valve stem 22a which extends through the packing box 23a in the upper end wall of the chamber 33 and carries at its upper end a snap-action double-ended valve 20a in the casing 34. This valve has two tandem heads 35 and 36 connected together by the neck 37. The head 35 has at its upper end a truncated tapered annular portion 38 adapted to a correspondingly shaped seat 39 in the casing 34. The part of the head enclosed by the annular seat 39 is exposed to any fluid pressure in the casing through the opening 40. The lower end of the head 36 has a truncated tapered annular portion 41 adapted to the annular seatl 42 in the lower part of the casing 34. The part of the head 36 enclosed by the annular seat 42 is, except as to the area occupied by the stem 22a, open to any fluid pressure in the casing 10. 43 is a passage which extends transversely through the casing 34 and leads from the interior of the casing 10 to the space therein occupied by the said valve and also from the said space into the interior of the member 13a. The valve member 20a has travel in the said space so that, when it is in its upper position, the portion of the head 35 below the annulus 38 acts as a valve to open the passage 43; and when it is in its lower position, with its annulus 41 on the seat 42, the

head 36 moves so as to be directly across the passage 43 and prevnt any iluid in the casing and above the passage 43 to enter the interior of the member 13a.

The casing 33 has the outwardly opening spring seated valve 32 having the same function as the valve 32 of Figsl 1 and 2.

Oil in the casing 10 being above the casing 34 and the double-headed valve 20a being in its lower position, compressed gas is applied to the surface of the oil in the annulus between the casing 10 and the well tubing 11 and the parts connected to its lower end. The said valve is held in its lower position because its upper end is subjected to a greater total pressure than its lower end. y

Compressed gas being admitted to the interior of the casing 10 transmits pressure through the oil, whose level is assumed to be above the valve casing 34, and gradually increases the pressure within the hollow spring 27 whose turns become more and more round until the force accumulated by spring and tending to move the valve 20a upwardly, overcomes the downward diierential of pressure on theends of the valve 20a, whereupon the spring 27 lengthens and pushes the valve 20a to its upper seat 39 where it is held by an upward differential of pressure on the lower end. This movement of the valve moves the head or valve member 35 away from the passage 43.

The compressed gas now gradually lowers the oil level in the annulus and forces oil through the passage 43 and into the member 13a and on up the well tubing 11 to the surface of the ground whence it is conducted to suitable receiving means. When the oil level reaches the passage 43 some of the gas on the oil escapes through the passage 43 and is thence j etted into the member 13a causing the oil to be levitated, that is, to become lighter' per cu. ft. than before. The gas jetted in globules into the oil expands and causes the mixture of oil and gas to flow up the tubing and out at the top ofthe well, thereby rel y ducing the pressure transmitted to the interior of the spring 27a. When the pressure is reduced sulciently, the spring contracts and overcomes the downward differential of pressure on the double-headed valve and pulls the valve to its lower or closed position with a snap action. The gas pressure continuing builds up again and forces the oil level down to the lower valve units, if any, which are successively openedand then closed in the manner just described.

Referring now to Fig. 4, the parts are mostly asin Fig.'1 and so far as the parts are identical in Figs. l and 4, the same reference characters are used on Fig. 4 as have been used on Fig. 1. I

In Fig. 4, the pipe 18 is omitted so that the Bourdon spring 27 is not in a sealed chamber but is subjected externally to such pressure as is transmitted from the column of liquid in the valve member 13.

The member 34a corresponding in a degree to the valve casing or member 34 in Fig. 3

has a' tapered exterior surface 44 resting on the annular tapered internal seat 45 in the coupling 46 inserted between lengths of the casing 10. The casing 34a has the chamber 47 having in its upper and lower walls valve seats 48 and 49 tapering downwardly. Tandem tapered valves 50 and 51 connected together and to the stem 52 which is carried by the anti-friction rinlgs 24 and 26 rest on their seats 48 and 49, respectively, when the Bourdon spring 27 is in its contracted state, and the valves are forced upwardly from their seats by the spring when the internal pressure in the spring exceeds the external pressure thereon by a predetermined amount.

The lower end of the spring is open to the rock or natural well pressure in the casing 10 at the lower end of the casing 34a by means of the passage 53. The chamber 47 between the valves 50 and 51 communicates with the passage 53 through the passage 54. The casing 34a has a chamber 55 below the seat 49, this chamber being connected to the chamber sage 56 which opens at the top of the casing The pump with its parts as shown in Fig. 4 having been lowered into a well so that the ports 14 are below the oil level in the casing 10 and until the surface 44 is on its seat 45 and continuous gaseous pressure being exerted on the oil in the annulus above the open ports 14 and 21, the oil in the annulus flows through these ports and up the tubing 11 and out therefrom at the top of the well, and its level in the annulus gradually sinks and the pressure on the exterior of the spring 27 gradually increases, while the pressure in the interior of the spring, being subject to the pressure of the head of oil below the casing 34a, remains constant. When the oil level in the annulus reaches the ports 14 and 21, the compressed gas escapes through the same and is jetted into the oil column in the valve member 13 and the tubing above. lAs with the apparatus of Figs. 1 and 3, this column of oil becomes gradually lighter per cu. ft. until the pressure en the exterior of the spring is sufliciently reduced to permit the pressure therein to accumulate force enough in thespring to overcome the weight of the moving parts and the resistance of the. balls 29, whereupon the sleeve valve member 20 is snapped upwardly closing the ports 14 and 21. 'At the same time the valves 50 and 51 are unseated and the oil beneath is forced up by the normal rock pressure through the seat 48 and down through the seat 49 and into the chamber enclosed/ by the wall 16 and thence into the valve member 13 and the tubing above. Consequently the external pressure on the exterior of the spring increases while that within the spring decreases until tendency of the spring to collapse pulls the valve member 20 down against the action of the balls 29 in the groove 31, whereupon the ports 14 and 21 are made to register with each other, and the valves and 51 are again seated. Some of the oil in the tubing then flows outwardly into the said annulus and above the ports 21. Rock pressure again builds up in the spring and artificial pressure on the oil again starts the cycle just described and it is repeated automatically.

The lower parts of Figs. 4 and 5 are alike and bear the same reference numerals; Fig. 5 has a modified form of valve mechanism in place of that'associated with the upper valve unit -or mechanism in Fig. 4. It also has substitute means for the balls 29 and the grooves 30 and 31 of Fig. 4.

In Fig. 5, the wall or casing 16 is screwed into the lower end of the valve casing 57 whose upper end-has thetapered collar or seal 58 resting on the seat 59 within the coupling 60 which connects two lengths of the casing 10. The valve stem 52 is prolonged upwardly and like Fig. 3 carries within the valve casing 57 a double-ended valve 20a having the heads 35 and 36 connected together by the member 37. The outer ends of the heads are truncated and are adapted to the respective seats 39 and 42. The casing 57 has the longitudinal passage 61 opening below into the chamber which is surrounded by the wall 16 and above into the well tubing 11, there being a downwardly seating check valve 62 at the upper end of the passage 61. A passage 63 extends longitudinally through the casing 57 opening below into the chamber 64 which communicates with the lower end of the head 36 within the annulus of the seat 42, and above into the annular space above the casing 57 and between the well casing and the Well tubing. A passage 43 connects the passages 61 and 63 to the central part of the chamber 65 in which the doubleend'ed valve works. A passage 66 connects the .passage 63 with the upper end of the chamber 65 through the opening around the annular seat 39.

' By providing the two valves 50 and 51 with the passages described in the valve casing 34a, the said valves are substantially balanced, and both the valve seats are swept with currents of oil, thereby keeping them free from sand and the like.

The oill in the casing 10 is assumed to be well above the coupling 60 before the pump string with its parts as shown is lowered into the Well. The pump string is lowered until the collar 58 comes to rest on the seat 59. The oil in the annulus between the well casing and tubing is subjected to the action of compressed gas, causing the oil level in the annulus to be lowered and theloil to flow down the passage 63 and through the passages 43 and 61 and past the check valve 62 and into the tubing 11 and thence to the surface of the ground. The double-ended valve has the outer ends of its head subjected to the pressure but the down pressure is obviously the greater. Thus the oil in the tubing is aerated or jetted as with the preceding forms of my invention. The action of the spring and valves 50, 51 are as in Fig. 4 and of the double-ended valve substantially the same as in Fig. 3. lVhen the pressure is reduced by the aeration and overiow of the oil in the well tubing, the diiiere'ntial between external and internal pressures on the spring 27 finally becomes suiiciently excessive internally to force the valve 22a to closed position and the valves 50 and 51 to open positions. This causes the head or valve 36 to close the passage 43 and thereby stop the aeration of the oil in the tubing. The valve 22a moves to its upper limit, the upper end of the head 35 going to its seat 39. As the area of the head 35 exposed to the gas pressure is less than the area on the head 36 exposed to that pressure, the valve 22a is held f/l Fig. 4, to cause the valves 50 Lacasse until the differential pressures on and in the spring are reversed, as in the ap aratus of andJ 51 to be again seated and the valve 22a to again open the passage 43. The head or valve 36 controls the port or passage 43 in a manner equivalent to that in which the sleeve valve member 20 controls the ports 14; and the differential pressure on the ends of the double-ended valve 22al provides resistances to the movement of the valves in either direction until the spring accumulates enough force to overcome the resistances and operate the valves with a snap action, the action and results being substantially those secured by the balls 29 and the grooves 30 `and 31 in Figs. 1 and 4.

In Fig. 6, the lower portions are substantially as in Fig. 4 and the upper portions mostly as in Fig. 5. The valve casing 345 has the external collar 44 which rests on the internal seat 45 of theA coupling 46a, while the valve casing 57a is not provided with y any seal with an annular seat in a coupling such as Fig. 5 has. In Fig. 6 the wall 16a which connects the two valve casings is not entirely closed like the wall 16 in Fig. 5, but has longitudinal slots 67.- The connects with a passage 63a which leads to the annulus between the casing 10 and the tubing 11, the passage 63a being provided with a check valve 68 seating downwardly f' to prevent sand from entering the valve casin 57a.

he oil level in the casing 10 being above the valve casing 57a when the pump string is lowered with the lparts as shown until the collar 44 comes to rest on its seat 45, coin-- pressed gas from the .tubing 11 Hows through the passages 61, 43 and 63a and into the said annulus and thence up the same to the surface of the ground. The gas which is jetted into the oil in the annulus above the check valve levitates the annular column of oil in the casing 10, causing the gradual reduction of pressure on the exterior surface of the spring 27. The natural pressure of the oil within the spring finally becomes suliiciently dominant over the lessening external pressure on the spring to lift the stem 52 4and cause the valves 50 and 51 to open and the double ended valve 20a to close the passage 43, as will be readily understood. The oil then flows up past the valves 50 and 51 and into the casing 10 and above the valve casing 57a. When the head of the oil vrises suiiiciently to cause the differential between the internal and external pressures on the spring vtobe reduced to a certain amount, the spring passage 43 the oil in the annulus above the check valve 68, and the cycle just described is automatically repeated.

69 is a slotted cage positioned within the lower end of the tubing and screwed on the upper end of the valve casing 57 a and over the upper end of the passage 61. The slots "70 in the cage prevent scale and the like from entering the valve casing 57a and interfering with action of the mechanism within the same.

Figs. 7 and 8 show a modification of the valve casing'34b of Fig. 6. The valve casing 340 in Figs. 7 and 8 uses cylindrical valves 50a and 51a in place of the truncated valves 50 and 51 of Figs. 4, 5, and 6. The parts are shown in their lower position with the head 50a acting as a valve whose periphery closes the passage 69 leading from the chamber 55 to the chamber 65a. As shown the natural or rock pressure of the oil in the well below the valve casing has access to the passage 53 leading to the interior of the spring 27 while the oil in the well is prevented from passing above the valve casing 340 by the valve 50a which also closes thel passage54 leading to the passage 53.

When the stem 52 is moved u by the spring as explained in the description of the operation of Fig. 6, the valve 50a passes above the passages 54 and 69 and the oil in the well below ows through the passages 53 and 54, between the heads 50a and 51a, through the passage 69 the chamber 55 and the L-shaped passage 56 into the member 16a which is open to the interior of the casing 10, the subsequent events being the same as those following the opening of the valves 50 and 51 of Fig. 6.

It will be understood that the spring will not expand unless a certain dierential of pressure obtains in the interior of the spring over that on the outside thereof. In Figs. -1 and 2where the artificial gas pressure is transmitted to the interior of the spring, the required differential has been provided for by enclosing the spring in a sealed chamber, thereby preventing the artiicial gas pressure from being transmitted to the exterior surface of the spring.

This differential is provided for in the remaining views by subjecting the exterior of the spring to the artificial gas pressure und the interior thereof 'to the natural or rock lpressure in the well.

I claim- 1. In a pump for oil wells, an inlet conduit, an outlet conduit, a valve for controlling the passage of oil from one conduit into the other, a spring of the Bourdon type for operating the valve, means permitting the rock pressure in the wall to be transmitted to onlyone surface of the spring, while the valve is closed and permitting pressure from compressed gas applied to the surface of the oil in the well to be transmitted to the other surface of the spring tofcreate a diierential pressure between the two surfaces of the spring for operating the valve in one direction, and means for jetting gas into the oil in the outlet conduit to discharge oil from the outlet conduit and to produce an approaching balance of the pressures applied to the said surfaces for operating the valve in the opposite direction.

2. In a pump for oil wells, an inlet conduit, an outlet conduit, a valve for controlling the passage of oil from one conduit into the other, a spring of the .Bourdon type for operating the valve, one surface of the spring being ex' posed only to `pressure in the inlet conduit while the valve is closedk and the other surface being exposed, when the valve is closed, to any pressures existent in the outlet conduit, and means for levitating the oil in the outlet conduit'whereby the pressure on the surface of the spring in that conduit may become reduced so as to permit the differential pressure on the said surfaces to actuate the spring and open the valve. A

3. ln a pump for oil wells, a vertical conduit in which oil in the well rises, a valve opening upwardly and dividing the oil column in the conduit into inlet and outlet columns, and a Bourdon spring attached to the valve for seating and unseatmg the valve, one surface of the spring being exposed only to pressure below the valve and the other surface to pressure above the valve while the valve is closed. s

4. ln a pump for oil wells, a vertical conduit in which oil in the well rises, a valve openingfupwardly and dividing the oil column in the conduit into inlet and outlet columns, and a Bourdon spring attached to the valve for seating and unseating the valve,

- the interior surface onlyo the spring being exposed to pressure below the valve while the valve is closed and the exterior surface to l pressure above the valve.

5.v In a ump foroil wells, a vertical conduit in` which oil in the well rises, a valve opening upwardly and dividing the oil column in the conduit into inlet and outlet columns, a Bourdon spring attached to the valve for seating and unseating the valve, one surface of the spring being exposed 'only to pressure below the valve while the valve is closed and the other surface to pressure above the valve, an inlet -conduit for compressed gas,

sure below the valve while the valve is closed Y an outlet conduit, a valve for controlling the passage of oil from one conduit into the other, a spring of the Bourdon type for operating the valve, one surface of the spring'l being exposed only to pressure in the inlet conduit while the valve is closed and the other surface being exposed, when the valve is closed, to any pressures existent in the outlet conduit, means for levitating the oil in the outlet conduit whereby the pressure on the surface of the spring in that conduitmay become reduced so as to permit the differential pressure on the said surfaces to actuate the spring and open the valve, and means preventing the operation of 'the valve until the spring has accumulated suiicient force to operate the valve gg with snap action.

8. ln a pump for oil wells a vertical conduit in which oil in the wellrises, a valve open upwardly and dividin the oil column in the conduit into inlet an outlet columns,

ya Bourdon spring attached to the valve for seating and unseating the valve, one surface of the spring being exposed only to pressure below the valve while the valve is closed and the other surface to pressure above the valve, loo

and means preventing the operation of the valve until the spring has accumulated sumcient force to operate the valve with snap action.

9. In a pump for oil wells, an inlet conduit,

an outlet conduit, a valve for controlling the passage of oil from one conduit into the other, a sprin of the Bourdon type for operating the v ve, means permitting the rock pressure in the well to be transmitted to only one surface of the s ring while the valve is closed, and permittmg pressure from compressed gas applied to the surface of the oil in the well to be transmitted to the other surface of the spring to create a differential pressure between the two surfaces of the spring for operating the valve in one direction, and means for jetting gas into the oil in the outlet conduit to discharge oil .from

the outlet conduit and to producel an approaching balance of the pressures applied to the said surfaces for operating the valve in the opposite direction, in combination with means for maintaining the valve open or closed until the springhas accumulated sufficient force to gvecomethe latter means and operate the'v'alve with a snapaction.

10. In anoil well pump, an inlet conduit, an outlet conduit, a. valve controlling the flow of o il from the former into the latter, *"l

automatic mea-ns for opening the valve, and means for balancing the oil pressure on the I upper and lower faces of the valve.

11. In a pump for oil wells, a'vertical conduit in which oil in the well rises, a valve open-upwardly anddividing the oil column in the conduit into inlet and outlet columns. a Bourdon spring attached to the valve for seating and unseating the valve, one surface of the spring being exposed to pressure below the valve and the other surface to pressure above the valve, and means independent of the said valve for causing delayed movement of the valve.

12. In a pump for oil wells, a vertiealconduit in which oil in the'well rises, a valve open upwardly and dividing the oil -column in the conduit into inlet and' outlet columns, a Bourdon spring attached to the valve for seating and unseating the valve, one surface of the spring being exposed to pressure below the valve Aand the other surface to pressureA above the valve, and means independent of the valve to ensure full opening and closing movements of the valve.

i 13. In a ump for oil Wells, a vertical conduit in whlch oil in the well rises, avalve open upwardly and dividing the oil column in the conduit into inlet and outletcolumns, a Bourdon spring attached to the valve for seating andunseating the valve,J one surface r of the spring being exposed to pressure below the valve and the other surface to pressure above the valve, and means independent of the valve to allowv the spring to build up' `a predetermined dileren'tial of external and lnternal pressures before the spring is able to operate the valve.

14..In a gas lift inlet conduit, an outlet conduit, a valve adapted to be submerged in the oil to be pumped and to control the passage of the oil from one conduit into the other, and a hollow resilient 'pressure member connected to the valve to operate it alternatelyjn opposite directions when predetermined differentials of pressure are reached between theinterior and exterior surfaces of the pressure member, Y' the interior ofthe pressure :rnem'ber being ex.- posed to the rock pressure ofthe oil. i 15.,In a. gas lift pump for, oil-wells, an

liuid in the inlet conduit is transmitted to the exterior surface of the pressure member.

16. In a pump for oil wells, a conduit up which oil in the well flows, a second conduit down which gas under pressure may be caused to travel, a valve between the two conduits and below the oil level in the first conduit, and a Bourdon spring attached to the valve and having its internal surface constantly open, one surface being open tothe rock pressure in the well while the other surface is open to a pressure independent of the source of rock pressure.

17. In a pump for oil wells, a conduit up which oil in the vWell flows, a; second conduit down which gas under pressure may be caused to travel, a valve between the two conduits and below the oil level in the first conduit, and a Bourdon spring attached to the valve and having its internal surface constantly opento the rock pressure in the well while the other surface is open to a pressure independent of the source of rock pressure.

In testimony whereof I hereunto alix my signature. i e

' MERTON T. ARCHER.

pump for oill wells, an

inlet conduit, an outlet conduit, a valve adapted to be submerged in the oil to be pumped and to control the passage of theioil from one conduit into 4the other, and a hollow resilient pressure member connected ,to

the valve to operate it alternately in opposite directions when predetermined di erentials of pressure larereache`d between th interior and exterior surfaces of the pressure member, the interior of the pressure member being ex' posed to the rock pressure of the oil, and therebeing provision whereby a reduced pressure exerted by gas introduced into the 

